Imaging the distribution of bitumen contaminants in shallow coastal plain sands in southwestern Nigeria using electrical resistivity

Abstract Naturally occurring bitumen seeps migrating within the shallow subsurface contaminates soil and groundwater in communities eastern segment of Dahomey Basin southwestern Nigeria. Managing these contaminations require an understanding distribution to isolate contaminated regions avoid farming activities or drilling drinking water wells them. Several studies have assessed occurrence region, focusing on their economic potentials but ignores challenges with contamination communities. This study focuses using electrical resistivity imaging techniques limited cores delineate Imakun-Omi community We used both 1D 2D numerical field approaches this study. 13 vertical soundings a Schlumberger electrode array were first acquired obtain bulk resistivities layer thicknesses. The alongside well lithologic data served as prior for forward modelling assess capability resolving electrically resistive coastal sands. Results guided acquisition five profiles image Wenner unit spacing 2 m. show that greater than 3000 Ohm-m are distributed top 4 m area extends down 10 some locations. Our despite difficulties sediments overlain by higher layers, reliable results can be derived, thus proving versatility delineating areas